AI: The Somnium Files follows Kaname Date, a detective who lost his memories and eye after an incident six years ago. He is assisted in his police work by Aiba, an advanced AI housed in his prosthetic eye. Together, they dive into a person's dream world, or Somnium, to uncover the truth that their conscious selves can't or won't reveal.
Date's newest investigation focuses on the death of a woman named Shoko Nadami, whose corpse was discovered with her left eye missing. As more bodies are discovered, each missing the left eye, it becomes apparent that they are the work of a serial killer dubbed the New Cyclops Killer. The case seems to have some connection to Date's missing memories and the Original Cyclops Serial Killings of six years ago... Gameplay is divided into real world and Somnium segments. In the real world, Date examines crime scenes and talks to persons of interest in a point-and-click format. When normal human vision is insufficient, Aiba's special vision modes can be used to examine the environment. Violent confrontations play out as quick time events in which Aiba runs simulations to guide Date through the fight safely.
In Somnium, the player directly controls Aiba in a subject's dream. The perception of time is different in a dream, and each action will shave a different amount of time off of the total. Players are given limited opportunities to change the length of time an action will take. By interacting with objects and solving puzzles based on dream logic, Aiba can break a subject's mental locks and uncover the truth. Certain Somnia have multiple solutions, which will send the player down different story paths. Only by playing every path can the case be fully solved.
